The present invention relates to a drive arrangement, comprising a motor drive shaft, which provides driving force of a motor, a working shaft, via which the drive arrangement delivers and receives operating torque, a coupling, which is set up to transmit torque from the motor drive shaft to the working shaft and from the working shaft to the motor drive shaft, and a brake arrangement which counters a rotational movement of the working shaft with a braking force. Furthermore, the invention relates to a flap control system that has a flap pivotally mounted about a pivot axis, a motor and a drive arrangement of the aforementioned kind.
In prior art, drive arrangements, in particular for the electromechanical driving of doors or flaps, are known, for example apparatuses for the electromechanical opening and closing of vehicle flaps. In the process, the force of the electric motor is transmitted by a coupling onto a working shaft bearing the flap. Depending on the field of application, situations also inevitably occur when using known apparatuses, in which a rotational movement is introduced into the drive arrangement by the working shaft. In particular, in the case of vertically moving flaps, operating torque is introduced into the drive shaft by the gravity of the flap. Furthermore, when using the drive arrangement by manual movement of the flap by the user, rotational movement can be introduced into the drive shaft.
In order to avoid an excessive load on the motor during torque transmission from the working shaft to the motor drive shaft or to prevent an unintentional adjustment of the flap (for example as a result of gravitational force) when the motor is switched off, known drive arrangements occasionally have brake arrangements, which counter the rotation of the shafts of the drive arrangement with a predetermined resistance. In the case of flaps moving in a vertical direction, the braking force of the brake arrangement is to be rated such that when the motor is idle, an autonomous downward movement of the flap is prevented such that the set pivot position of the flap is retained. In addition, brake arrangements are known, which fix a certain turning position between working shaft and motor drive shaft when the motor is idle in order to prevent a manual rotation of the motor by the user and therefore a potential overload of the motor.
In the case of drive arrangements with brake arrangements of the kind referred to above, the disadvantage emerges that the braking effect of the brake arrangement must be overcome by the motor when operating the drive arrangement in order to start the working shaft rotating. The use of a brake arrangement described above therefore works at the cost of energy efficiency when operating the drive arrangement.
Against the background of his problem, the object of the present invention is to provide a drive arrangement and a flap control system which have a high functional range and at the same time work with high energy efficiency.